US2008044070A1PendingUtilityA1
Abnormal mass candidate detecting apparatus, method and computer-readable medium
Est. expiryAug 16, 2026(~0 yrs left)· nominal 20-yr term from priority
Inventors:Yao Nie
G06T 7/0012G06T 2207/30068A61B 6/502
40
PatentIndex Score
0
Cited by
0
References
0
Claims
Abstract
An apparatus, a computer-readable medium and a method of detecting cancer masses using mammography are described. From an input image, an iris contrast map and an iris ring filter response map of the input image are generated. Potential abnormal mass candidates are identified by locating those masses whose iris contrast value above a predetermined contrast threshold and whose iris ring filter response is above a predetermined response threshold. After the potential abnormal mass candidates are identified, candidates that are less likely to be abnormal can be eliminated.
Claims
exact text as granted — not AI-modified1 . A method to detect an abnormal mass candidate from an input image, comprising:
generating an input gradient vector map based on the input image, wherein the input gradient vector map is a map of vector values of pixels of the input image, and wherein the vector value for each pixel represents a direction and a magnitude of a change of the pixel in the input image within a small neighborhood of the pixel; generating an iris contrast map based on the input gradient vector map, wherein the iris contrast map is a map of iris contrast values of the pixels of the input image, and wherein the iris contrast value for each pixel represents a response value of a corresponding pixel in the input gradient vector map to an iris contrast filter; generating an iris ring filter response map based on the iris contrast map, wherein the iris ring filter response map is a map of iris ring filter response values of the pixels of the input image, and wherein the iris ring filter response value for each pixel represents a response value of a corresponding pixel in the iris contrast map to an iris ring filter; and outputting, as the abnormal mass candidate, a location of a pixel of the input image in which both the iris contrast and the iris ring filter response values of the pixel is greater than or equal to a minimum iris contrast threshold and greater than or equal to a minimum iris ring filter response threshold, respectively.
2 . The method of claim 1 , wherein the step of generating the input gradient vector map comprises:
generating an input gradient angle map based on the input image, wherein the input gradient angle map is a map of angles of the pixels of the input image, and wherein the angle for each pixel represents the direction of the change of the pixel in the input image within the small neighborhood of the pixel; and generating an input gradient magnitude map based on the input image, wherein the input gradient magnitude map is a map of scalar values of the pixels of the input image, and wherein the scalar value for each pixel represents the magnitude of the change of the pixel in the input image within the small neighborhood of the pixel.
3 . The method of claim 1 , wherein the step of generating the iris contrast map comprises:
outputting a response C(x,y) by applying the iris contrast filter for each
C
(
x
,
y
)
=
max
0
≤
r
≤
l
-
d
1
d
∑
i
=
r
+
1
R
C
i
pixel location of the input image such that
C
i
=
1
M
∑
j
=
1
M
A
ij
cos
θ
ij
,
wherein C(x,y) is the iris contrast value of the pixel location, A ij is a vector magnitude of a pixel i,j from the input gradient vector map, θ ij is an angle between a vector direction of the pixel i,j from the input gradient vector map and a line segment connecting the pixel i,j to a center of the iris contrast filter, r is an inner radius of the iris contrast filter, d is a width of a ring of the iris contrast filter, R is an outer radius of the iris contrast filter such that R=r+d, l is an upper limit of R, and M is a number of directions,
wherein the iris contrast filter is centered on the pixel location (x,y), and
wherein r is adaptive and d is fixed.
4 . The method of claim 3 , wherein the step of generating the iris ring filter response map comprises:
generating an iris contrast gradient angle map based on the iris contrast map, wherein the iris contrast gradient angle map is a map of contrast angles of the pixels of the input image, and wherein the contrast angle for each pixel represents a direction of a change of a corresponding pixel in the iris contrast map within a small neighborhood of the corresponding pixel; and outputting a response D(x,y) through one of
applying the iris ring filter for each pixel location such that
D
(
x
,
y
)
=
max
0
≤
r
≤
l
-
d
1
M
∑
j
=
0
M
-
1
Dj
D
j
=
1
d
∑
i
=
r
+
1
R
cos
θ
ij
,
or
applying a half-ring iris ring filter for each pixel location such that
D
(
x
,
y
)
=
max
0
≤
r
≤
l
-
d
{
max
0
≤
k
≤
M
-
1
1
M
/
2
∑
j
=
k
mod
(
k
+
M
/
2
-
1
,
M
)
Dj
}
D
j
=
1
d
∑
i
=
r
+
1
R
cos
θ
ij
,
wherein D(x,y) is the iris filter response value of the pixel location, θ ij is an angle between the contrast angle of a pixel i,j from the iris contrast gradient angle map and a line segment connecting the pixel ij to a center of the iris ring filter or the half-ring iris ring filter, r is an inner radius of the iris ring filter or the half-ring iris ring filter, d is a width of a ring of the iris ring filter or the half-ring iris ring filter, R is an outer radius of the iris ring filter or the half-ring iris ring filter such that R=r+d, l is an upper limit of R, and M is a number of directions, and
wherein the iris ring filter or the half-ring iris ring filter is centered on the pixel location (x,y), and
wherein r is adaptive and d is fixed.
5 . The method of claim 4 , wherein the step of generating the iris ring filter response map further comprises:
selecting one or more pixel locations each of whose iris contrast value is greater than equal to the minimum iris contrast threshold; and outputting the responses D(x,y) only for the selected pixel locations.
6 . The method of claim 3 , wherein the step of generating the iris contrast map further comprises:
adjusting the input gradient vector map prior to applying the iris contrast filter, wherein the step of adjusting the input gradient vector map comprises performing for each pixel (x,y) of the input gradient vector map:
centering a mask filter of a predetermined size on the pixel (x,y);
determining Amin, wherein Amin is a minimum magnitude of the pixels within the mask filter from the input gradient vector map; and
outputting adjusted magnitude Aout for the pixel such that Aout=Axy−Amin, wherein Axy is the magnitude of the pixel (x,y) from the input gradient vector map.
7 . The method of claim 1 , wherein the step of generating the iris contrast map comprises:
outputting a response C(x,y) by applying the iris contrast filter for each pixel location of the input image such that
C
(
x
,
y
)
=
max
0
≤
r
≤
l
-
d
1
d
∑
i
=
r
+
1
R
C
i
C
i
=
median
{
A
ij
cos
θ
ij
,
j
=
1
,
2
,
…
,
M
}
,
wherein C(x,y) is the iris contrast value of the pixel location, A ij is a vector magnitude of a pixel i,j from the input gradient vector map, θ ij is an angle between a vector direction of the pixel i,j from the input gradient vector map and a line segment connecting the pixel i,j to a center of the iris contrast filter, r is an inner radius of the iris contrast filter, d is a width of a ring of the iris contrast filter, R is an outer radius of the iris contrast filter such that R=r+d, l is an upper limit of R, and M is a number of directions,
wherein the iris contrast filter is centered on the pixel location (x,y), and
wherein r is adaptive and d is fixed.
8 . The method of claim 7 , wherein the step of generating the iris contrast map further comprises:
adjusting the vector magnitude A ij of the pixel i,j from the input gradient vector map such that
A
ij
=
{
A
ij
,
A
ij
<
A
max
A
ij
·
exp
(
-
(
A
ij
-
A
max
)
2
/
B
)
,
else
prior to applying the iris contrast filter to output C(x,y),
wherein Amax is a predetermined maximum magnitude value and B is a predetermined divisor.
9 . The method of claim 7 , wherein the step of generating the iris ring filter response map comprises:
generating an iris contrast gradient angle map based on the iris contrast map, wherein the iris contrast gradient angle map is a map of contrast angles of the pixels of the input image, and wherein the contrast angle for each pixel represents a direction of a change of a corresponding pixel in the iris contrast map within a small neighborhood of the corresponding pixel; and outputting a response D(x,y) through one of
applying the iris ring filter for each pixel location such that
D
(
x
,
y
)
=
max
0
≤
r
≤
l
-
d
1
M
∑
j
=
0
M
-
1
Dj
D
j
=
1
d
∑
i
=
r
+
1
R
cos
θ
ij
,
or
applying a half-ring iris ring filter for each pixel location such that
D
(
x
,
y
)
=
max
0
≤
r
≤
l
-
d
{
max
0
≤
k
≤
M
-
1
1
M
/
2
∑
j
=
k
mod
(
k
+
M
/
2
-
1
,
M
)
Dj
}
D
j
=
1
d
∑
i
=
r
+
1
R
cos
θ
ij
,
wherein D(x,y) is the iris filter response value of the pixel location, θ ij is an angle between the contrast angle of a pixel i,j from the iris contrast gradient angle map and a line segment connecting the pixel i,j to a center of the iris ring filter or the half-ring iris ring filter, r is an inner radius of the iris ring filter or the half-ring iris ring filter, d is a width of a ring of the iris ring filter or the half-ring iris ring filter, R is an outer radius of the iris ring filter or the half-ring iris ring filter such that R=r+d, l is an upper limit of R, and M is a number of directions, and
wherein the iris ring filter or the half-ring iris ring filter is centered on the pixel location (x,y), and
wherein r is adaptive and d is fixed.
10 . The method of claim 9 , wherein the step of generating the iris ring filter response map further comprises:
selecting one or more pixel locations each of whose iris contrast value is greater than equal to the minimum iris contrast threshold; and outputting the responses D(x,y) only for the selected pixel locations.
11 . The method of claim 7 , wherein the step of generating the iris contrast map further comprises:
adjusting the input gradient vector map prior to applying the iris contrast filter, wherein the step of adjusting the input gradient vector map comprises performing for each pixel (x,y) of the input gradient vector map:
centering a mask filter of a predetermined size on the pixel (x,y);
determining Amin, wherein Amin is a minimum magnitude of the pixels within the mask filter from the input gradient vector map; and
outputting adjusted magnitude Aout for the pixel such that Aout=Axy−Amin, wherein Axy is the magnitude of the pixel (x,y) from the input gradient vector map.
12 . The method of claim 1 , wherein the step of outputting the location as the abnormal mass candidate comprises:
determining whether the location is part of a mass already identified as being abnormal by another location of the input image; and outputting the location as the abnormal mass candidate when it is determined that the location is not part of the mass already identified as being abnormal by the another location of the input image.
13 . The method of claim 12 , wherein the step of determining whether the location is part of the mass already identified as being abnormal comprises:
determining whether the location is within a minimum threshold distance from the another location; and determining that the location is part of the already identified mass when it is determined that the location is within the minimum threshold distance from the another location.
14 . The method of claim 1 , wherein the location is one of a plurality of abnormal mass candidates, the step of outputting the location as the abnormal mass candidate comprises:
determining an order of the location among the plurality of the abnormal mass candidates based on one or both of the iris contrast map value and the iris ring filter response value corresponding to the location; and outputting the location as the abnormal mass candidate when the order of the location is within a predetermined maximum number of candidates.
15 . The method of claim 1 , wherein the step of outputting the location as the abnormal mass candidate comprises:
determining whether the location is within a predetermined region, wherein the predetermined region is at least one of a chest wall region, a shoulder region, a skin line region, and a pectoral muscle region; and outputting the location as the abnormal mass candidate when it is determined that the location is not within the predetermined region.
16 . The method of claim 1 , further comprising:
determining a contrast value level from the iris contrast map such that only a predetermined number of locations or only a predetermined percentage of locations of the input image have iris contrast values greater than or equal to the contrast value level; and setting the contrast value level as the minimum iris contrast threshold.
17 . An abnormal mass candidate detection apparatus, comprising:
an input gradient vector map generating device configured to generate an input gradient vector map based on an input image, wherein the input gradient vector map is a map of vector values of pixels of the input image, and wherein the vector value for each pixel represents a direction and a magnitude of a change of the pixel in the input image within a small neighborhood of the pixel; an iris contrast map generating device configured to generate an iris contrast map based on the input gradient vector map, wherein the iris contrast map is a map of iris contrast values of the pixels of the input image, and wherein the iris contrast value for each pixel represents a response value of a corresponding pixel in the input gradient vector map to an iris contrast filter; an iris ring filter response map generating device configured to generate an iris ring filter response map based on the iris contrast map, wherein the iris ring filter response map is a map of iris ring filter response values of the pixels of the input image, and wherein the iris ring filter response value for each pixel represents a response value of a corresponding pixel in the iris contrast map to an iris ring filter; and an abnormal mass candidate outputting device configured to output, as the abnormal mass candidate, a location of a pixel of the input image in which both the iris contrast and the iris ring filter response values of the pixel is greater than or equal to a minimum iris contrast threshold and greater than or equal to a minimum iris ring filter response threshold, respectively.
18 . The apparatus of claim 17 , wherein the iris contrast map generating device comprises:
an iris contrast filtering device configured to output a response C(x,y) by applying the iris contrast filter for each pixel location of the input image such
C
(
x
,
y
)
=
max
0
≤
r
≤
l
-
d
1
d
∑
i
=
r
+
1
R
C
i
that
C
i
=
1
M
∑
j
=
1
M
A
ij
cos
θ
ij
,
wherein C(x,y) is the iris contrast value of the pixel location, A ij is a vector magnitude of a pixel i,j from the input gradient vector map, θ ij is an angle between a vector direction of the pixel i,j from the input gradient vector map and a line segment connecting the pixel i,j to a center of the iris contrast filter, r is an inner radius of the iris contrast filter, d is a width of a ring of the iris contrast filter, R is an outer radius of the iris contrast filter such that R=r+d, l is an upper limit of R, and M is a number of directions,
wherein the iris contrast filter is centered on the pixel location (x,y), and
wherein r is adaptive and d is fixed.
19 . The apparatus of claim 18 , wherein the iris ring filter response map generating device comprises:
an iris contrast gradient angle map generating device configured to generate an iris contrast gradient angle map based on the iris contrast map, wherein the iris contrast gradient angle map is a map of contrast angles of the pixels of the input image, and wherein the contrast angle for each pixel represents a direction of a change of a corresponding pixel in the iris contrast map within a small neighborhood of the corresponding pixel; and an iris ring filtering device or a half-ring iris ring filtering device or both, wherein the iris filtering device is configured to output a response D(x,y) by applying an iris ring filter for each pixel location such that
D
(
x
,
y
)
=
max
0
≤
r
≤
l
-
d
1
M
∑
j
=
0
M
-
1
Dj
D
j
=
1
d
∑
i
=
r
+
1
R
cos
θ
ij
,
wherein the half-ring iris ring filtering device is configured to output the response D(x,y) by applying a half-ring iris ring filter for each pixel location such that
D
(
x
,
y
)
=
max
0
≤
r
≤
l
-
d
{
max
0
≤
k
≤
M
-
1
1
M
/
2
∑
j
=
k
mod
(
k
+
M
/
2
-
1
,
M
)
Dj
}
D
j
=
1
d
∑
i
=
r
+
1
R
cos
θ
ij
,
wherein D(x,y) is the iris filter response value of the pixel location, θ ij is an angle between the contrast angle of a pixel i,j from the iris contrast gradient angle map and a line segment connecting the pixel i,j to a center of the iris ring filter or the half-ring iris ring filter, r is an inner radius of the iris ring filter or the half-ring iris ring filter, d is a width of a ring of the iris ring filter or the half-ring iris ring filter, R is an outer radius of the iris ring filter or the half-ring iris ring filter such that R=r+d, l is an upper limit of R, and M is a number of directions, and
wherein the iris ring filter or the half-ring iris ring filter is centered on the pixel location (x,y), and
wherein r is adaptive and d is fixed.
20 . The apparatus of claim 18 , wherein the iris contrast map generating device further comprises:
a gradient magnitude adjusting device configured to adjust the input gradient vector map from the input gradient vector map generating device, wherein the adjusted input gradient vector map is provided to the iris contrast filtering device, and wherein the gradient magnitude adjusting device is configured to adjust the input gradient vector map by performing for each pixel (x,y) of the input gradient vector map:
centering a mask filter of a predetermined size on the pixel (x,y);
determining Amin, wherein Amin is a minimum magnitude of the pixels within the mask filter from the input gradient vector map; and
outputting adjusted magnitude Aout for the pixel such that Aout=Axy−Amin, wherein Axy is the magnitude of the pixel (x,y) from the input gradient vector map.
21 . The apparatus of claim 17 , wherein the iris contrast map generating device comprises:
a median iris contrast filtering device configured to output a response C(x,y) by applying the iris contrast filter for each pixel location of the input image such that
C
(
x
,
y
)
=
max
0
≤
r
≤
l
-
d
1
d
∑
i
=
r
+
1
R
C
i
C
i
=
median
{
A
ij
cos
θ
ij
,
j
=
1
,
2
,
…
,
M
}
,
wherein C(x,y) is the iris contrast value of the pixel location, A ij is a vector magnitude of a pixel i,j from the input gradient vector map, θ ij is an angle between a vector direction of the pixel i,j from the input gradient vector map and a line segment connecting the pixel i,j to a center of the iris contrast filter, r is an inner radius of the iris contrast filter, d is a width of a ring of the iris contrast filter, R is an outer radius of the iris contrast filter such that R=r+d, l is an upper limit of R, and M is a number of directions,
wherein the iris contrast filter is centered on the pixel location (x,y), and
wherein r is adaptive and d is fixed.
22 . The apparatus of claim 21 , wherein the iris contrast map generating device further comprises:
a gradient magnitude adjusting device configured to adjust the input gradient vector map from the input gradient vector map generating device, wherein the adjusted input gradient vector map is provided to the median iris contrast filtering device, and wherein the gradient magnitude adjusting device is configured to adjust the input gradient vector map by performing for each pixel i,j of the input gradient vector map, adjusting the vector magnitude A ij of the pixel i,j from the input gradient vector map such that
A
ij
=
{
A
ij
,
A
ij
<
A
max
A
ij
·
exp
(
-
(
A
ij
-
A
max
)
2
/
B
)
,
else
prior to applying the iris contrast filter to output C(x,y), where Amax is a predetermined maximum magnitude value and B is a predetermined divisor.
23 . The apparatus of claim 21 , wherein the iris filter response map generating comprises:
an iris contrast gradient angle map generating device configured to generate an iris contrast gradient angle map based on the iris contrast map, wherein the iris contrast gradient angle map is a map of contrast angles of the pixels of the input image, and wherein the contrast angle for each pixel represents a direction of a change of a corresponding pixel in the iris contrast map within a small neighborhood of the corresponding pixel; and an iris ring filtering device or a half-ring iris ring filtering device or both, wherein the iris filtering device is configured to output a response D(x,y) by applying an iris ring filter for each pixel location such that
D
(
x
,
y
)
=
max
0
≤
r
≤
l
-
d
1
M
∑
j
=
0
M
-
1
Dj
D
j
=
1
d
∑
i
=
r
+
1
R
cos
θ
ij
,
wherein the half-ring iris ring filtering device is configured to output the response D(x,y) by applying a half-ring iris ring filter for each pixel location such that
D
(
x
,
y
)
=
max
0
≤
r
≤
l
-
d
{
max
0
≤
k
≤
M
-
1
1
M
/
2
∑
j
=
k
mod
(
k
+
M
/
2
-
1
,
M
)
Dj
}
D
j
=
1
d
∑
i
=
r
+
1
R
cos
θ
ij
,
wherein D(x,y) is the iris filter response value of the pixel location, θ ij is an angle between the contrast angle of a pixel i,j from the iris contrast gradient angle map and a line segment connecting the pixel i,j to a center of the iris ring filter or the half-ring iris ring filter, r is an inner radius of the iris ring filter or the half-ring iris ring filter, d is a width of a ring of the iris ring filter or the half-ring iris ring filter, R is an outer radius of the iris ring filter or the half-ring iris ring filter such that R=r+d, l is an upper limit of R, and M is a number of directions, and
wherein the iris ring filter or the half-ring iris ring filter is centered on the pixel location (x,y), and
wherein r is adaptive and d is fixed.
24 . The apparatus of claim 21 , wherein the iris contrast map generating device further comprises:
a gradient magnitude adjusting device configured to adjust the input gradient vector map from the input gradient vector map generating device, wherein the adjusted input gradient vector map is provided to the iris contrast filtering device, and wherein the gradient magnitude adjusting device is configured to adjust the input gradient vector map by performing for each pixel (x,y) of the input gradient vector map:
centering a mask filter of a predetermined size on the pixel (x,y);
determining Amin, wherein Amin is a minimum magnitude of the pixels within the mask filter from the input gradient vector map; and
outputting adjusted magnitude Aout for the pixel such that Aout=Axy−Amin, wherein Axy is the magnitude of the pixel (x,y) from the input gradient vector map.
25 . The apparatus of claim 17 , wherein the abnormal mass candidate outputting device is configured to output, as the abnormal mass candidate, the location of a pixel of the input image in which the iris contrast response value of the pixel is greater than or equal to the minimum iris contrast threshold in the event that no locations exists with a iris ring filter response value that is greater than or equal to the minimum iris ring filter response threshold.
26 . A computer-readable medium in which a program executable on a computer for detecting an abnormal mass candidate from an input image is recorded, the program comprising the steps of:
generating an input gradient vector map based on the input image, wherein the input gradient vector map is a map of vector values of pixels of the input image, and wherein the vector value for each pixel represents a direction and a magnitude of a change of the pixel in the input image within a small neighborhood of the pixel; generating an iris contrast map based on the input gradient vector map, wherein the iris contrast map is a map of iris contrast values of the pixels of the input image, and wherein the iris contrast value for each pixel represents a response value of a corresponding pixel in the input gradient vector map to an iris contrast filter; generating an iris ring filter response map based on the iris contrast map, wherein the iris ring filter response map is a map of iris ring filter response values of the pixels of the input image, and wherein the iris ring filter response value for each pixel represents a response value of a, corresponding pixel in the iris contrast map to an iris ring filter; and outputting, as the abnormal mass candidate, a location of a pixel of the input image in which both the iris contrast and the iris ring filter response values of the pixel is greater than or equal to a minimum iris contrast threshold and greater than or equal to a minimum iris ring filter response threshold, respectively.Join the waitlist — get patent alerts
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